A sintered body of aluminum titanate has a low thermal expansion coefficient and high corrosion resistance, and is known as a heat-resistant material which exhibits low wettability with molten metal, corrosion resistance, spalling resistance and other excellent properties when used as a material for container, ladle, gutter, etc., for molten metal of aluminum, aluminum alloys, pig iron or the like. However, since the crystal grains constituting a sintered body of aluminum titanate are anisotropic, the sintered body has drawbacks that the micro crack formation at the crystal grain boundary often occurs due to the stress caused by thermal expansion, and that the mechanical strength is easily weakened pursuant to the progress of micro cracks and gaps.
Thus, a conventional sintered body of aluminum titanate is insufficient in strength, and, particularly, can not exhibit sufficient durability when used under high temperature and loaded conditions.
Further, since aluminum titanate is unstable at temperatures of 1280° C. or below and easily decomposed into TiO2 and Al2O3 when used under high temperature conditions of approximately 800 to 1280° C., it is difficult to continuously use the sintered body of aluminum titanate within such temperature range.
In order to improve sinterability of aluminum titanate and restrain the thermal decomposition thereof, additives such as silicon dioxide are mixed with the raw material for sintering. In this case, however, the refractoriness of the obtained sintered body is easily diminished, and it is not possible to obtain a sintered body of aluminum titanate having refractoriness so as to be usable in high temperatures over about 1400° C. and also possessing high mechanical strength.